Optical Networks

Abstract

Improvements in or relating to Optical Networks. The invention relates to improvements in or relating to optical networks, and methods and an apparatus for providing communications services. Receiving an optical signal is described comprising a carrier wavelength and optical data. The optical data is substantially erased, and the carrier wavelength is re-modulated with user data for onward transmission of the user data.

1 . An apparatus arranged to receive a modulated optical signal comprising a carrier wavelength and optical data, the apparatus arranged to substantially erase the data from the optical signal, to receive user data, and to modulate the carrier wavelength with the user data for onward transmission of the user data. 
     
     
         2 . An apparatus according to  claim 1 , arranged to split the received optical signal into at least two portions, each portion comprising the modulated optical signal. 
     
     
         3 . An apparatus according to  claim 1 , and further including an optical amplifier. 
     
     
         4 . An apparatus according to  claim 3 , wherein the optical amplifier is a reflective semiconductor optical amplifier. 
     
     
         5 . An apparatus according to  claim 3 , wherein the optical amplifier is operable to substantially erase the data from the optical signal, to receive user data, and to modulate the carrier wavelength with the user data for onward transmission of the user data. 
     
     
         6 . An apparatus according to  claim 3 , wherein the optical amplifier is arranged to be operated substantially at its gain saturation threshold. 
     
     
         7 . An apparatus according to  claim 1 , arranged to transmit at least one of the modulated optical signal in a downstream direction, and to transmit the user data in an upstream direction. 
     
     
         8 . An apparatus according to  claim 1 , and further arranged to transmit the received optical data to a user device. 
     
     
         9 . A method of providing communications services, the method including:
 receiving a modulated optical signal comprising a carrier wavelength and optical data;   substantially erasing the data from the optical signal;   receiving user data; and   modulating the carrier wavelength with the user data for onward transmission of the user data.   
     
     
         10 . A method according to  claim 9 , and further including splitting the received optical signal into at least two portions, each portion comprising the modulated optical signal. 
     
     
         11 . A method according to  claim 9 , and further including substantially erasing the data from the optical signal, receiving user data, modulating the carrier wavelength with the user data, and transmitting the user data using an optical amplifier. 
     
     
         12 . A method according to  claim 11 , and further including using a reflective semiconductor optical amplifier as the optical amplifier. 
     
     
         13 . A method according to  claim 11 , and further including operating the optical amplifier substantially at its gain saturation threshold. 
     
     
         14 . A method according to  claim 9 , including transmitting at least one of the modulated optical signal in a downstream direction, and transmitting the user data in an upstream direction. 
     
     
         15 . A method according to  claim 9 , and further including transmitting the received optical data to a user device. 
     
     
         16 . A communications network including an apparatus according to  claim 1 . 
     
     
         17 . A communications network arranged to perform a method of providing communications services, the method including:
 receiving a modulated optical signal comprising a carrier wavelength and optical data;   substantially erasing the data from the optical signal;   receiving user data; and   modulating the carrier wavelength with the user data for onward transmission of the user data.